Clinical Trial

A Study to Confirm Safety and Efficacy of Lecanemab in Participants With Early Alzheimer's Disease

Study acronym: Clarity AD
Active, Not Recruiting Phase 3
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Summary
This study will be conducted to evaluate the efficacy of lecanemab in participants with early Alzheimer's disease (EAD) by determining the superiority of lecanemab compared with placebo on the change from baseline in the Clinical Dementia Rating-Sum of Boxes (CDR-SB) at 18 months of treatment in the Core Study. This study will also evaluate the long-term safety and tolerability of lecanemab in participants with EAD in the Extension Phase and whether the long-term effects of lecanemab as measured by the CDR-SB at the end of the Core Study is maintained over time in the Extension Phase. Extension Phase Part B will continue dosing with lecanemab in countries where lecanemab may not be commercially available.
Protocol Amendment History 18 amendments
This ClinicalTrials.gov record has been amended 18 times since 2019-03-21; most recent amendment 2026-04-01.
Status change: Recruiting → Active, Not Recruiting 2021-10-18
Trial Details
NCT Number NCT03887455
Lead Sponsor Eisai Inc.
Collaborators: Biogen
Conditions Early Alzheimer's Disease
Enrollment 1,906 participants
Start Date 2019-03-27
Primary Completion 2029-06-30 (estimated)
Study Completion 2029-06-30 (estimated)
Updated on ClinicalTrials.gov 2026-04-07